Gambling Grouse: Private Wet-Meadows or Public Mesic Rangelands

Article by John Carlson, Sage-Grouse Implementation Lead for the Montana/Dakotas Bureau of Land Management; Patrick Donnelly, IWJV Spatial Ecologist, and Hannah Nikonow, IWJV Sagebrush Communications Specialist

Sage-grouse chick, photo courtesy of the USFWS

The perils of sagebrush country are extreme for young sage-grouse chicks. After hatching, the hen quickly marches her brood of four-inch-tall camouflaged fluffballs with toothpick legs away from the nest. They are on a quest to find the food they needed to live. In their first months of life, chicks cannot yet digest sagebrush, and the succulent forbs and insects found in productive wet meadow “mesic habitats” are their sole foods. The greater the distance chicks need to trudge to find this food the lower their survival.

In the Great Basin sage-grouse must walk twice the distance to find mesic habitats compared to other sage-grouse in the West. Here mesic habitats are located in two places: at low-elevations in privately owned riparian wet meadows, wetlands, or agricultural fields, and at high elevation in publicly owned rangelands kept green by melting snowpack. In the spring, sage-grouse hens often place their nest in strategic locations close to mesic habitats to minimize a chick’s need to hike long distances and increase their chances of survival.

While this strategy seems safe, sage-grouse hens are making a calculated gamble. When snowpack is plentiful, high elevation public rangelands provide abundant habitat that allows birds to disperse making them harder for predators to locate. Favorable conditions in high elevations during wet years means more chicks survive and sage-grouse populations grow. During drought the gamble doesn’t pay out, because high elevation range lands become dry and unproductive. During dry periods private low elevation wet meadows are very important, because they are more drought resilient and help to carry long-lived sage-grouse hens and their chicks through hard times until habitat conditions improve.

From Donnelly et al. 2019 - Sage-grouse range divided into different ecological regions based on mesic habitat sensitivity to drought. In the Great Basin and Rocky Mountains the majority of high elevation mesic rangelands are within publicly owned BLM and U.S. Forest Service boundaries.

Much of mesic habitat conservation has successfully been focused on privately-owned wet meadows, but this approach may only be addressing half the bird’s needs, particularly where a majority of high elevation mesic rangelands occur within Bureau of Land Management (BLM) and U.S. Forest Service boundaries. Conservation of these sites not only benefits sage-grouse, but public lands mule deer, elk herds, and livestock that rely on productive mountain summer range during times of year when low elevation conditions are poor.

Sage-grouse access to mesic habitats may be jeopardized by encroaching conifer that are creating new barriers to bird movements between upper and lower elevations. Sage-grouse avoid otherwise suitable habitat when conifer trees cover just 4% of a sagebrush rangeland landscape. From a sage-grouse perspective, these areas are too risky to travel through, nest in, or try to raise chicks in. In addition to providing hiding cover and perches for predators, every invading tree in sagebrush country acts like a giant straw in the ground sucking up gallons of water a day and decreasing water available for grasses and forbs. The trees also result in a faster evaporation of snowpack, further robbing arid rangeland habitats of precious water.

Sage-grouse need the conservation of both public and private mesic habitats so they have access to these crucial habitats during seasons of either drought or deluge. These findings come from recent science supported by BLM and encourages land managers to identify that a diversity of mesic resources rather than any single type to conserve the places that sustain grouse populations over time. Emerging public lands strategies including targeted removal of invasive conifer may also assist in the re-establishment of sage-grouse nesting and brood rearing habitat as well as travel routes that connect upper and lower elevation mesic habitats cutoff by conifer encroachment.

As more frequent and intensifying droughts are forecasted in coming decades, conserving water resources will be critical to the maintenance of western wildlife. To improve the odds of sage-grouse survival now is the time to double down on a conservation strategy with both practices of mesic area restoration and conservation as well as conifer removal in the right places to connect key high elevation public mesic rangelands with low elevation private wet meadows.

For more information on this research you can find the published paper here: J.P. Donnelly, D.E. Naugle, et. al. 2018. Seasonal drought in North America’s sagebrush biome structures dynamic mesic resources for sage-grouse. Ecology & Evolution 8:12492-12505. Contact: Patrick_Donnelly@fws.gov or david.naugle@umontana.edu.

Photo courtesy of Patrick Donnelly